This part of the book features a running example project that will thread through the various chapters. Well illustrate many of the points we made in using this example project. The project is real—its not an academic exercise—and weve taken snapshots during the various iterations of modeling, prototyping, and coding.

This being a book about agile development (i.e., adapting to changing requirements over time), our idea is to present the original project requirements and show that even though the requirements evolved over the course of the project, we were still able to incorporate up-front modeling into the development process. The story that unfolds is very much the story of how to approach this situation.

The use case text and diagrams shown in this parts chapters were taken directly from the project, so youll notice some (minor) inconsistencies at times between the use cases and the text in the diagrams. This also reflects the agile spirit: the analysis and design artifacts need to be just good enough to get us to the next stage of development. (Or, to put it another way, they need to be minimal yet sufficient . The team should always try to avoid spending ages polishing the diagrams until theyre perfect.)

Chapter 5: Introducing the Mapplet Project

Overview

This project tells the story of a feedback-driven process that causes the design and the code to become more tightly in sync as the project progresses. To us, this is the essence of successful agile development. In most cases where modeling is done up-front, the model and the code quickly diverge, never to meet again. Agile ICONIX, on the other hand, encourages developers to keep the model and the code tightly synchronized, by revisiting and reviewing the model at the end of each iteration (and at the start of each new release phase), as well as by placing an emphasis on early feedback at every stage of the process. We revisit this concept in more detail in Chapters 7.

Our example project is a map-based hotel finder for a travel website, which was developed using the agile development approach described in this book. We’ll show the evolution of the model and the code that goes with it.

The finished product is available for you to interact with at this web address: http://smartmaps.vresorts.com. Just drill down into any of the map destination pages from the main U.S. map, and then click the Show Map button to see the mapplet in action. You might find it interesting to compare the finished product with the use cases presented in this book.

The mapplet is a web-based application that is built on top of ESRI’s ^[1.] ArcGIS Server platform. The ArcGIS ^[2.] platform enables the development of Geographic Information System (GIS) or map-based applications using state-of-the-art OO (e.g., C#/.NET) environments. To fully leverage the power of these modern development environments, it’s helpful to adopt an OO approach from front to back. ICONIX Process, being a low-ceremony, minimalist, use case–driven design approach, is ideal for developing OO GIS applications. The mapplet example is actually an ArcGIS Server application that has been developed by ESRI’s Professional Services organization.

The mapplet example shows how to run from requirements and use cases through detailed OO design, to C#/.NET source code and fully working software that meets the project requirements. A key element of the approach is the “agile” strategy of interleaving modeling and coding through multiple releases of the design.

^[1.] See www.esri.com.

^[2.] See the sidebar “What Is ArcGIS?” later in this chapter.